Share Email Print
cover

Proceedings Paper

Temperature-dependent optical properties of Cd0.96Zn0.04Te substrate material
Author(s): Manuel A. Quijada; Anne Marie Russell; Robert J. Hill
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

We report cryogenic optical properties of Cd0.96Zn0.04Te wafers that are used as substrate layers in the manufacturing of HgCdTe focal-plane array detectors. These studies are motivated by the fact that the substrate optical properties influence the overall detector performance. The studies consist of measuring the substrate frequency dependent transmittance T(ω) and reflectance R(ω) above and below the optical band-gap in the UV/Visible and infrared frequency ranges, and with temperature variation of the sample from 5 to 300 K. Analysis of these data shows the index of refraction n shows slight dispersion in the transparent 1-6 μm range of CdZnTe. Furthermore, n exhibits a weak reduction in the average value (~ 4%) when the sample temperature is reduced from 300 K to 5 K. These measurements also show that the optical gap near 1.49 eV at 300 K increases to 1.62 eV at 5 K. Finally, we observe sharp absorption peaks near this gap energy at low temperatures. The close proximity of these peaks to the optical transition threshold suggests that they originate from the creation of bound electron-hole pairs or excitons. The decay of these excitonic absorptions may contribute to a photoluminescence and transient background response of these back-illuminated HgCdTe CCD detectors.

Paper Details

Date Published: 18 August 2005
PDF: 11 pages
Proc. SPIE 5904, Cryogenic Optical Systems and Instruments XI, 59040Q (18 August 2005); doi: 10.1117/12.618734
Show Author Affiliations
Manuel A. Quijada, Goddard Space Flight Ctr. (United States)
Anne Marie Russell, GST, Goddard Space Flight Ctr. (United States)
Robert J. Hill, SSAI, Goddard Space Flight Ctr. (United States)


Published in SPIE Proceedings Vol. 5904:
Cryogenic Optical Systems and Instruments XI
James B. Heaney; Lawrence G. Burriesci, Editor(s)

© SPIE. Terms of Use
Back to Top